Pimp my Rotring rapid PRO 0.5

This is a follow-up blog post to my earlier blog post about the Rotring rapid PRO 0.5.

The Rotring rapid PRO is a stunningly beautiful mechanical pencil, at least the black version is …for my taste. As you might remember the sliding sleeve was the worst performing sliding sleeve I have seen so far.

My Rotring rapid PRO 0.5 taken apart

The purpose of a sliding sleeve

The main purpose of a sliding sleeve is, in my opinion, to slide back while you write so that you can keep writing without having to press the button / use whatever mechanism there is to advance the lead.

If the sliding sleeve doesn’t slide back easily you might as well got for a retractable sleeve, one that is either all the way in or out. This make the pencil pocket safe and allows work that is more suitable for drafting purposes, too.

On the unmodified rapid PRO 0.5 you had to use a force of about 1.2 N to get the sleeve to move – far too much to make the sleeve slide back automatically while you write.

The Rotring rapid PRO 0.5's sleeve

The sleeve

Pimp my sliding sleeve

Having never explored how the sliding sleeve mechanism works I assumed ‘simple’ friction is responsible for the force needed to slide the sleeve. The problem is: I thought it’s the friction between the sleeve and grip section holding the sleeve (the grip section can be seen on the left in the first picture). To reduce the friction I took the sleeve out and started removing material from the sleeve on my Spyderco Sharpmaker. This made the sleeve thinner, something I had hoped would reduce the friction, but after a while I noticed that this treatment didn’t help making the sleeve slide easier at all.

The Rotring rapid PRO 0.5's sleeve on a Spyderco Sharpmaker

Trying to reduce the friction – the wrong way: the sleeve on a Sharpmaker

I then figured out that the friction holding the sleeve in place must be caused by the white plastic holder at the bottom of the sleeve. I started using the file from my Swiss Army knife1 to remove some of the plastic, i.e. making the plastic holder narrower, but that took too long, so in the end I just cut bits of the plastic off with the knife.

This time it worked. Great!

Trying to file some of the plastic off....

Trying to file some of the sleeve holder’s plastic off….

From 1.2 N to 0.2 N

The result: You now only need about 0.2 N to slide the sleeve of my rapid PRO, which makes it suitable for writing without having to advance the lead all the time. This is an amazing result – because of the bigger lead diameter you can’t compare an 0.5 mm sleeve directly to the 0.2 mm sleeve of the Orenz. Just the friction caused by the 0.5 mm lead in the rapid PRO’s sleeve (i.e. just these two parts, ‘outside’ the pencil) means that you need 0.1 N just to slide the sleeve down the lead – that’s without the additional force needed to slide the sleeve within the pencil barrel/ grip section.

If I’d have to do it all again I obviously wouldn’t make the metal sleeve narrower. It made the sleeve a bit more wobbly, but it is not really an issue. It is certainly still less wobbly than a Kuru Toga or Muji’s flat clip mechanical pencil.

That's one small scrape off [a] sleeve, one giant leap in the friction chart.

That’s one small scrape off [a] sleeve, one giant leap in the friction chart.

More about the Cloud Book in the blog post, I’m still using it regularly.

  1. Fun fact: I got this knife from my godfather in the 1980s and I believe it is the same model as the one that the astronauts used on the Space Shuttle, just mine has a cork screw instead of a screw driver. []
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Monocle again

Well, after having had a look at Japanese stationery in issue 81 the current issue of Monocle, number 88, includes a Bavaria survey. Quite a few Franconian companies are included as well and even though there are only five sentences in the magazine about Faber-Castell the editors must have thought pencils are sexy enough to put them on the cover of the latest issue.

Faber-Castell on the cover of Monocle magazine

Faber-Castell on the cover of Monocle magazine

They also have a paragraph on Gmund paper, the company that makes the golden envelopes for the Oscars and provides the paper for other big events and companies.

I believe that showing a photo of parts of the Monocle cover in this blog post falls under “fair dealing” as described by the UK Copyright service.

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The Kuru Toga – an old hat? 2

This isn’t really a follow up to my 2009 blog post The Kuru Toga – a disappointment, t’s more of a separate blog post – by coincidence I’ve come across a document I want to share.

As consumers we usually see Schmidt as a manufacturer of pen refills, but they actually do manufacture a lot of pens. If you look at their catalogue you can see pen parts that look as if Schmidt is manufacturing pens or parts of pens for big companies like Lamy and Montblanc.

They also seem to invent a lot and are very innovative when it comes to pens, even though very often we don’t see these inventions in mass market products. Just one example, I remember reading about a fountain pen they invented that uses microscopic pumps to transport the ink to the nib.

Well, it looks as if they have also invented something very similar to the Kuru Toga, just that they did this 25 years before Uni / Mitsubishi.  You can read more about it in this patent: DE 3641432 C1 , but be warned: Google’s translation of this patent isn’t brilliant.


It even looks a bit like the Kuru Toga

It even looks a bit like the Kuru Toga (Image from Schmidt’s patent document)

I assume I can show the image from the patent here (‘fair dealing’), as the patent is available to look at via Google anyway.

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Affordable pencils 2

Gourmet Pens latest blog post gave me a shock. £5.25 (~$8.15; €7.15) for Coccoina glue? Did Coccoina glue get that expensive? Looking at the price development of wood cased pencils in last week’s blog post was probably really boring as pencils seem to be one of the most price stable items in the world of stationery.

From my twitter feed. Each horizontal line represents a pencil that kept it's price over the last few years.

From my twitter feed. Each horizontal line represents a pencil that kept it’s price over the last few years.

I had a look in my old emails and found Coccoina orders from 2008 and 2009 where I paid £2.50 (in today’s exchange rate: $3.90; €3.40) each. I think at the time another shop sold them cheaper, but postage wise I could combine the glue order with other items so I ordered it for £2.50. According to Measuring Worth  £2.50 in 2008 is still less than £3 in 2015.

Well, I guess the message here is pencils are (still) great value for money.


PS: Regarding the shelf life of Coccoina, being mentioned at Gourmet Pens: I always had luck reviving dried out Coccoina with a few drops of water.

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Tactile Turn Gist

I’m interested in the Tactile Turn Gist, but am not sure yet whether I should back this project on Kickstarter. I probably will, but I am also not sure which combination to pick. So much choice. I had a few questions I tried to answer by searching on the web and thought what I found might also be interesting for others, too.


The nib

The Campaign page states these are Bock #6 nibs. I have heard of them, but have never used them, so my first question was: how do they perform, especially: are they springy? I prefer springy nibs to stiff nibs.

#6 seems to refer to the fact that the nib feed has a diameter of 6mm.  If you want to know more about Bock: The Southern Scribe wrote about a visit to the Bock factory.

According to Peter Unbehauen’s video a Bock titanium nib seems to be more flexible than than a Bock gold nib, which again is more flexible than a Bock steel nib, which seems quite stiff. The nibs used for the Gist might be different, but this might give you an initial idea about the nibs. I am sure The Pen Addict talked about the nibs in the podcast, espeiclaly the Titanium one, but but I don’t remember the details, just that it is a different writing experience and podcasts aren’t easily searchable. If I have more time I will check again.

Diagram showing the different prices for the different Gist materials

You know it’s serious when I get the Eberhart Faber Blackwing 602 out to do a diagram.

The materials


According to the Campaign page polycarbonate is like Makrolon, the material used for the Lamy 2000. I guess the Gist will feel different to the Lamy 2000 because of the different surface, but it makes me think that the pen, if ordered in this material will be very durable. Nice.


Brass sharpeners have more or less disappeared, partly because brass often contains lead to make the material easier to work with, but new regulations in many parts of the world want to ban lead or put warning labels on these products because of possible health effects. Lead free brass is available, but usually comes with a higher price tag. 360 Brass, as used for the Gist, seems to contain lead which makes me think whether I should pick another material if I back this Kickstarter.


Lead also seems to be common in many copper alloys. I haven’t yet figured out what 145 Copper is and whether it contains lead. I will need to find the time to find out more and expand this blog post.

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